Apparatus for continuous strip casting

Abstract

An apparatus for continuously casting thin strip includes a caster having a pair of casting rolls having a nip there between capable of delivering cast strip downwardly from the nip and an first enclosure capable of forming a protective atmosphere into which the strip can be formed in loop to extend over a plurality of rollers into pinch rolls with the strip having a strain of less than 0.4%, which may be provided by a plurality of rollers at entry of the strip into the pinch rolls to carry the strip into the pinch rolls, with at least a first entry roller having a diameter between 200 and 650 millimeters and being below a majority of other rollers.

Description

BACKGROUND AND SUMMARY[0001]This invention relates in general to the casting of metal strip by continuous casting in a twin roll caster.[0002]In a twin roll caster, molten metal is introduced between a pair of counter-rotated laterally positioned casting rolls that are internally cooled so that metal shells solidify on the moving casting surfaces and are brought together at a nip between the rolls to form a solidified strip product, delivered downwardly from the nip between the rolls. The term “nip” is used herein to refer to the general region at which the casting rolls are closest together. The molten metal may be poured from a ladle into a smaller vessel or series of smaller vessels from which it flows through a metal delivery nozzle located above the nip, forming a casting pool of molten metal supported on the casting surfaces of the rolls immediately above the nip and extending along the length of the nip. This casting pool is usually confined between side plates or dams held i...

AI Technical Summary

Benefits of technology

[0003]Further, the twin roll caster may be capable of continuously producing cast strip from molten steel through a sequence of ladles. Pouring the molten metal from the ladle into smaller vessels before flowing through the metal delivery nozzle enables the exchange of an empty ladle with a full ladle without disrupting the casting campaign of cast strip.

[0005]The conditions provided for the just cast strip in the first enclosure influences the quality of the cast strip. We have found that microcracks in the surface of the finish cast strip can be traced to strain in the strip in the first enclosure as it moves through the loop and across the roller table into the first pinch rolls. Additionally, we have found that the oxygen and water vapor levels of the atmosphere in the first enclosure increase oxidation and scale formed on the strip and otherwise influence the surface quality of the cast strip. The present invention provides an apparatus for continuously casting thin strip having improved conditions for the strip after casting in the first enclosure.

Problems solved by technology

Additionally, we have found that the oxygen and water vapor levels of the atmosphere in the first enclosure increase oxidation and scale formed on the strip and otherwise influence the surface quality of the cast strip.

Images